Buildings have direct environmental impacts, ranging from the use of raw materials for their construction and renovation to the consumption of natural resources, like water and fossil fuels, and the emission of harmful substances. Data on heating energy consumption were collected during the audits of 193 European residential buildings in five countries. The available data were analysed in order to assess the influence of envelope thermal insulation, age and condition of heating system, on the heating energy consumption and the resulting environmental impact. About 38% of the audited buildings have an annual heating energy consumption more than the European average (174.3 kWh/m2), about 30% of the buildings have higher airborne emissions than the European averages and 23% of the buildings have higher solid waste emissions than the European averages. Polish buildings have the highest average heating energy consumption (63% of the buildings above the European average). French and Polish buildings have the highest production of airborne emissions, while Polish buildings have the highest emissions of solid wastes.